Are there any advantages to having the 93 tune over the 87?? More performance or gas milage? Sorry if this is a dumb question.

 

I think thats a good question because I dont know the answer, and I would also like to know

 

Cool then, Can someone help us out?

 

As I understand it, the higher the octane tune, the more performance that is obtainable, i.e. rear wheel horsepower increase.

Some say a little better MPG - if you can keep your foot off the floor board.....

 

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Thanks

 

You can advance the timing more with the higher octane, which will make more H.P.

 

You get more HP with higher octane (as mentioned already), but I've noticed no increase in gas mileage with the 93 octane tune over 87 octane.

 

Ditto for me. Running C and L intake with 93 octane. Big difference in power and when driven easy I gained about 1.5 mpg.
Scott

 

I had some interesting results when I dynoed with 87 then 93.

In a sheer moment of genuis, my mechanic mistakenly loaded the 93 tune from DTP on my XCAL2, thinking it was the 87 tune. Well, I had 87 octane fuel in the tank during the first pull. Yes, that's right, we made a dyno pull with the 93 octane tune loaded and had 87 octane in the tank! Result: No pinging. :scratch: and virtually identical HP and TQ #'s as when we ran the 93 fuel with the 93 tune Go figure. This was on a SuperFlow Dyno, which he claims is very accurate. This was on back to back pulls with a cool down and fuel change wedged in between.

As far as fuel economy, I can't help you there. I've been driving like Steve McQueen since the 4.10's, JLT and XCAL2. :drive:

 

Interesting. I guess if there was no pinging, there would be no harm doing this? I was thinking about switching back to 87 octane today since I really don't run mine that hard. Maybe I'll see what it does with 93 octane tune first before changing it.

 

Hi,
Eighty-seven, 91 or 93 octane fuel all have the same heating values. The difference is in the postponement of the knocking temperature. When fuel burns at about 500 feet per second, you have what is called a normal burning rate. When the unburned end-gas in the combustion chamber gets over a certain temperature & pressure (because the flame-front is approaching it, thereby compressing it and heating it too), you can jump to a 1,500 to 2,000 feet per second "explosion speed" in the combustion chamber, slamming the piston, and giving that characteristic knock sound.
The higher the octane rating of the fuel, the higher the temperature & pressure required to enter the knock phase of combustion. By advancing the timing, your fuel burns sooner and is available to do more expansion work in forcing the piston down. If you buy higher octane fuel and get a programmer to advance the timing curve, you should be getting higher power levels and greater fuel economy.
Don’t allow your engine to knock for anything more than a moment, as it can cause bearing wear by crashing through the hydrodynamic film, and even burn through pistons, break connecting rods, etc.. Knock is a bad thing.
Brian.

 

I can tell you that the Premium, Mid, and Regular fuel programs I give customers are not the same. You will make more power with the Premium program over the Regular.

Here is a little info to help back up the post above. The 05 GT for the most part has a great knock sensor. Un-like the older stangs you should in theory be able to load a premium tune with cheap gas and as long as the air is correct your engine will use as much timing as it can take and not ping. It will simply not advance the timing is knock is detected.

I dont tell our customers to do that but it should work. Also some gas stations gas is better than others so if you have a premium fuel loaded and have the option of 92 or 94 octane (We can get 94 at the pump in Indiana) you may likely make more power with the 94 because your engine may be able to advance more timing.

There are a lot of other factors also but that is a sort of easy way to explain it.

 

My mpg with all of my mods and 93 octane is 22 mpg combined. With 87 octane I get 21.6 mpg combined. I drive my car hard at times too. The best that I got was 25 mpg all hwy with 93 octane.

 

dump question:

all the modern european and asian engines, i know, adjust theirself for the gas. You can use all the available gas (without diesel naturally).

Does it the mustang V8 to?

my importer says: Use "normal gas" here in germany. it has 91 octane (the cheaperst gas you can get ($ 5,70 per gallon)

the next better level is "super gas" it has 95-96 octane ($5,90)

and the best is called "super plus" or "optimax", 99-101 octane ($6,-) that's for use in high performance engines like bmw and others.

My old mercedes runs better with higher octan. The new mustang too?

Thank's

 

It will only run better if you tune it for the higher octane gas. Just switching the gas w/o adjusting the timing with a tune won't do you any good.

 

I havent experimented with different octane levels, but I read that the '05 has the fuel and spark advance curves factory tuned for premium fuel. You would think that if you put in 92 octane, there would be some small performance boost, but I dont know for sure. Maybe someone could test this theory and report back to us?

 

I cant remember which, but one of the mustang specific magazines, I think, did do some dyno runs with only 93 octane vs 87 octane and noticed some hp gain, I will look at my archives and see which one and post results and issue.

Well, I cant find it. In fact, now I am doubting my accuracy, but I swear i read somewhere that someone saw gains (4-5 hp) just from switching from 87-93 octane, everything else bone stock. If someone else remembers this help a brother out.

 

I'd like to see more on that also.

 

Hmm. I think I'll start runnin' 91 from now on. Im eventually going to get the C&L/Predator anyway, so it will be interesting to see if just switching fuels will make any noticeable difference. The car only holds a lousy 16 gallons anyway, so I doubt the cost difference will break me!

 

It works out to about a penny per mile. So what's that? Between $100 - $200 per year? Or $2 - $4 per week? One fast food meal costs more than that.